“Perhaps there is a police officer somewhere who would interpret an automobile passenger’s giving him the finger as a signal of distress...

...But the nearly universal recognition that this gesture is an insult deprives such an interpretation of reasonableness."

That was Second Circuit Judge Jon O. Newman in an opinion all about the middle finger.  Here's the intro to the opinion:

An irate automobile passenger’s act of “giving the finger,” a gesture of insult known for centuries,1 to a policeman has led to a seizure of two persons ordered to return to an automobile, an arrest for disorderly conduct, a civil rights suit, and now this appeal. Plaintiffs-Appellants John Swartz (“John”) and his wife, Judy Mayton-Swartz (“Judy”), appeal the July 8, 2011, judgment of the United States District Court for the Northern District of New York (David N. Hurd, District Judge) granting summary judgment to Defendants-Appellees Richard Insogna, a St. Johnsville, New York, police officer, and Kevin Collins, an officer with the Montgomery, New York, Sheriff’s Department.
 
Accepting, as we must at this stage of the litigation, the Plaintiffs’ version of the facts, we vacate the judgment and remand for further proceedings.

I like footnote 1: See Bad Frog Brewery, Inc. v. New York State Liquor Authority, 134 F.3d 87, 91 n.1 (2d Cir. 1998) (reporting the use of the gesture by Diogenes to insult Demosthenes). Even earlier, Strepsiades was portrayed by Aristophanes as extending the middle finger to insult Aristotle. See Aristophanes, The Clouds (W. Arrowsmith, trans., Running Press (1962)). Possibly the first recorded use of the gesture in the United States occurred in 1886 when a joint baseball team photograph of the Boston Beaneaters and the New York Giants showed a Boston pitcher giving the finger to the Giants. See Ira P. Robbins, Digitus Impudicus: The Middle Finger and the Law , 41 U.C. Davis L. Rev. 1403, 1415 (2008).


The NY Times has more:

There is usually no mistaking the act or intent of extending a middle finger.

John Swartz was arrested in May 2006 after he raised his middle finger upon spotting a police radar device in St. Johnsville, N.Y. An officer says he thought Mr. Swartz might be seeking help.

Take John Swartz, for example. In May 2006, Mr. Swartz was a passenger in a car in a rural part of upstate New York when he spotted a police car that was using a radar speed-tracking device.

Mr. Swartz, a Vietnam veteran and retired airline pilot, acted on instinct to show his displeasure: he extended his right arm outside the passenger’s side window, and then further extended his middle finger over the car’s roof.

The reaction was swift. The officer followed the car; words were exchanged; backups were called; and Mr. Swartz was arrested on a charge of disorderly conduct.

He later filed a civil rights lawsuit, and although a lower court judge dismissed the case, the prestigious United States Court of Appeals for the Second Circuit in Manhattan reversed that decision on Thursday, ruling that Mr. Swartz’s lawsuit can go forward.

The appellate decision offers a rich thumbnail sketch of the history and significance of the raised middle finger, one that traces possibly the first recorded use of the gesture in the United States to 1886, “when a joint baseball team photograph of the Boston Beaneaters and the New York Giants showed a Boston pitcher giving the finger to the Giants.”

Mr. Swartz’s intent, 120 years later, was undoubtedly similar.

He made the gesture as his fiancée and now wife, Judy Swartz, was driving on the Sunday evening before Memorial Day through St. Johnsville, a village of under 2,000 people, about 50 miles northwest of Albany.

“I couldn’t see the officer, didn’t know who he was,” Mr. Swartz, 62, recalled on Thursday. He explained that his gesture was provoked by his anger that the local police were spending their time running a speed trap instead of patrolling and solving crimes.

“It was very disheartening,” Mr. Swartz said. “They’d do it constantly to the point where they ignored all of their other duties.”